Sandbox c7

 1ACJ shows the crystal structure of Torpedo californica acetylcholinesterase (TcAChE) complexed with tacrine.

Tacrine is a parasympathomimetic and a centrally acting cholinesterase inhibitor.

It was the first centrally-acting cholinesterase inhibitor approved for the treatment of Alzheimer's disease.

Tacrine’s ring is stacked between the aromatic rings of tryptophan 84 and phenylalanine 330 .W84 and F330

This is the time when blood comes into action. Blood is a specialized body fluid that delivers necessary substances to the body's cells – such as nutrients and oxygen – and transports waste products away from those same cells. Because oxygen is not very soluble in blood, animals have an efficient mechanism for capturing oxygen, transporting, and releasing it by the inner cells: hemoglobin.

Harel M, Schalk I, Ehret-Sabatier L, Bouet F, Goeldner M, Hirth C, Axelsen PH, Silman I, Sussman JL. Quaternary ligand binding